680 On the Local and Relative Geology of Singapore, [July, 



of iron solutions in clays on exposure to the air, and the combustion of 

 rocks by heated ferruginous gas are chemically related, and the product 

 of these two processes, geologically so widely sundered, is sometimes 

 difficultly distinguishable by the eye. Ancient conglomeritic and brec- 

 ciated laterites and ferruginous rocks, appear to have been formed in 

 many localities at, or soon after, the period of the ferruginous emissions 

 by fragments or pebbles settling down in a sandy or clayey base saturat- 

 ed with ferruginous water. Similar conglomerates, breccias and sand- 

 stones are at present forming along the coasts where the hills or banks 

 above contain much iron ; but all these are very obviously distinguish- 

 able from the original plutonically laterised sedimentary rocks. 



When I visited Malacca about two years ago I had paid very little 

 attention to these subjects and had not formed the preceding views. 

 When an opportunity occurred at the beginning of last month of 

 revisiting the place, I eagerly seized the occasion of testing these views 

 in a new locality, and one which had been described by Geologists, such 

 as Captain Newbold, and Dr. Ward, familiar with the much vexed 

 laterites of southern India. Captain Newbold, in his work on the Straits 

 describes the Malacca hills " as being generally of granite with the 

 exception of a few near the sea coast, which are of laterite overlying the 

 granite. Specimens of hornblende rock have been brought to me, he 

 continues, from a hill a little south of Malacca — the islets on the coasts 

 are of granite of various kinds, with white, red and green felspar. In 

 all, the felspar appears to be predominant, and mica deficient." Dr. 

 Ward says of the Malacca leterite — " In all its properties it agrees exact- 

 ly with the rock common on the Malabar coast and described by Dr. 

 Buchanan under the name of laterite. 5 ' I was now therefore, for the 

 first time, in a position to bring my theory to the strongest test, for I had 

 not seen any specimen of Indian laterite, and could only compare some 

 of the apparently analogous Singapore rocks with it from descriptions. 

 Captain Newbold, in one of the latest of his numerous papers on the 

 Geology of Southern India, describes very minutely the often mention- 

 ed laterite of Beder and makes some remarks on the long debated ques- 

 tion of origin. He combats the idea that it is a contemporaneous 

 rock associating with trap, or a product like trap of igneous fusion. He 

 also casts doubt on the theory, advocated by several Geologists, of the 

 laterite being " nothing more than the result of the recent disintegra- 



